Springs in a car: what group of parts do they belong to and why is it important for repairs?

When it comes to car suspension, many people think of shock absorbers, springs or levers, but they often forget about springs - one of the oldest, but still relevant elements of the ride. Springs do not just “help” the suspension, but play a key role in distributing the load, softening shocks and maintaining vehicle stability. However, even experienced car owners cannot always answer accurately. What group of parts do springs belong to? — to elastic elements, guiding or damping? This confusion leads to errors in diagnostics, selection of spare parts and even repairs.

In this article we will look at the place of springs in the classification of automotive parts, how they differ from springs and shock absorbers, and why they are often classified as elastic suspension elements — but with important caveats. You will learn how springs are designed, where they are used (spoiler: not only in trucks!), and what mistakes mechanics make when servicing them. And also why incorrect classification can cost you money when buying spare parts.

Classification of springs in a car: an elastic element or part of the suspension?

According to GOST 25816-83 and modern technical standards, springs belong to elastic suspension elements — along with springs, torsion bars and air springs. Their main task is convert the kinetic energy of impacts (from road irregularities) into potential deformation energy, and then return it back, ensuring smooth running. However, there is a nuance here: unlike coil springs, springs simultaneously perform guiding function, fixing the position of the axle or axle relative to the body.

This duality is often misleading. For example, in textbooks on car design, springs may be referred to as:

• 🔧 Elastic elements (the main function is vibration absorption).
• 🚛 Part of the dependent suspension (by design - they connect the wheels of one axle).
• 🔄 Guide devices (according to an additional role - they limit the movement of the bridge).

This “multitasking” makes the springs unique. For example, in passenger cars (where they are rare) they are classified strictly as elastic elements, and in trucks and SUVs — also to the suspension guide parts. This affects the approach to repair: if in the first case it is enough to replace the worn spring, then in the second case it may be necessary to adjust the geometry of the bridge.

The difference between springs and springs and shock absorbers: why they should not be confused

A common mistake is to call springs “springs” or “shock absorbers.” These are fundamentally different details and should not be confused. Let's look at the key differences:

Characteristics	Springs	Springs	Shock absorbers
Main function	Elasticity + direction of movement of the bridge	Resilience only (shock absorption)	Damping (vibration damping)
Construction	Set of steel sheets (plates)	Twisted metal rod	Hydraulic/gas cylinder
Application	Trucks, trailers, SUVs, retro cars	All types of cars (usually cars)	All types of cars (work in tandem with springs/springs)
Service life	150–300 thousand km (depending on load)	100–200 thousand km	60–120 thousand km

Important point: Springs and shock absorbers always work in tandem. The spring softens the impact, and the shock absorber dampens vibrations, preventing the body from “swinging”. If the shock absorber fails, the spring will begin to work in extreme mode - this will lead to its accelerated wear (the appearance of cracks or metal “fatigue”). And vice versa: a broken spring will overload the shock absorber, and it may “break through” at the first serious impact.

⚠️ Attention: In trucks (for example, KAMAZ or MAN) springs are often equipped with additional rubber buffers, which take on part of the load when fully loaded. If the buffer is worn out, the spring will “break” - this reduces its life by 30–40%.

Where springs are used: from retro cars to modern trucks

Although springs are primarily associated with trucks, they are used in other types of vehicles as well. Here are the key applications:

• 🚚 Trucks: KAMAZ, Scania, Volvo FH — here the springs can withstand loads of up to 10–12 tons per axle. Often used multi-leaf springs (5–7 plates) with progressive stiffness.
• 🏜️ SUVs and body-on-frame SUVs: UAZ Patriot, Toyota Land Cruiser 70, Mercedes G-Class — springs provide high maneuverability and maintainability.
• 🚗 Vintage cars: Volga GAZ-21, Ford Model T, Citroën 2CV — here the springs are combined with a dependent suspension for simplicity of design.
• 🚛 Trailers and semi-trailers: Spring suspensions are cheaper and more reliable than pneumatics, so they are installed on spreader trailers or onboard platforms.

Interesting fact: in sports cars Springs are almost never used due to their weight and insufficient adjustment accuracy. However, in rally cars (for example, Lada Vesta WTCC) is sometimes used combined systems — springs + air suspension to adjust ground clearance.

Why did springs disappear from most passenger cars?

In the 1980s and 1990s, manufacturers massively switched to spring suspensions due to several reasons:

1. Weight: Springs are 20–30% heavier than springs, which worsens dynamics and fuel consumption.

2. Comfort: The springs adapt better to small irregularities (for example, “washboard”).

3. Cost: Manufacturing multi-leaf springs requires precise heat treatment and assembly, which is more expensive than producing coil springs.

4. Setting: The stiffness of springs is easier to select for a specific model, while springs require selection based on the number of sheets and their thickness.

Spring design: how they are designed and what they are

A spring is not just a “pack of metal plates”. Its design is dictated by the need to combine elasticity, strength and durability. Let's look into the details:

Main spring elements:

1. Root leaf - the thickest and longest, takes the main load. Has holes for mounting to the frame.
2. Radical sheets - shorter and thinner, providing progressive stiffness.
3. Tie clamps — fix the sheets, preventing them from moving.
4. Bushings and pins - connect the spring to the bridge and frame.
5. Rubber gaskets - reduce noise and vibration.

According to their design, springs are divided into:

• 📏 Multileaf - classic version (5–9 sheets), used in trucks.
• 🔄 Few-leaved (parabolic) - 1–3 sheets of variable thickness, lighter and softer (for example, in Ford Ranger).
• 🔗 Transversal - transverse springs, used in older models (for example, Volga GAZ-24).
• 🚜 Conical — with wedge-shaped sheets for progressive stiffness (SUVs).

🔍 Cracks or tears in sheets

🔍 Spring deflection of more than 10% of the original height

🔍 Creaking or knocking noise when driving over uneven surfaces

🔍 Uneven tire wear (indicates a violation of the bridge geometry)

🔍 Visible corrosion on 30% of the sheet area

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Typical spring malfunctions: how to diagnose and what to do

Springs break less often than shock absorbers, but their malfunctions are more dangerous - they can lead to loss of control (especially in trucks). Let's look at the main problems and their symptoms:

1. Fatigue cracks

Occur due to constant loads or overload. They are dangerous because the leaf can break apart on the fly, which will lead to displacement of the bridge. Signs: creaking when the body rocks, visible cracks on the underside of the sheets.

2. Deflection (subsidence)

The spring “sits” due to prolonged use or exceeding the load capacity. Signs: the car “sags” to one side, ground clearance decreases. In trucks this leads to uneven tire wear and deterioration in controllability.

3. Corrosion

Particularly dangerous for springs with sand-salt treatment roads in winter. Rust reduces the strength of metal by 40–50%. Signs: red spots, blistering paint, crunching noise under load.

4. Loosening the clamps

If the clamps become loose, the sheets begin to rub against each other, which leads to accelerated wear. Signs: loud creaking when driving over uneven surfaces, play between sheets.

⚠️ Attention: In trucks with air suspension springs often play a role emergency elastic element — if the air cylinder is deflated, the load will fall on the spring. If it is worn out, the machine may “sit on the bridge” even if the system is partially depressurized!

How to choose springs: what to look for when buying

Choosing springs is a more complex task than buying springs or shock absorbers. Here it is important to take into account not only the car model, but also operating conditions. Here are the key criteria:

1. Spring type

For passenger cars (for example, UAZ Hunter) will fit few leaf parabolic - they are softer and lighter. For trucks (for example, Scania R420) are needed multileaf with progressive hardness.

2. Material

High-quality springs are made of alloy steel 50HGFA or 60S2A followed by hardening. Cheap analogues made from ordinary steel last 2–3 times less.

3. Number of sheets

The more sheets, the stiffer the spring. For example:

- 3–4 sheets: SUVs and light trucks (GAZelle).

- 5–7 sheets: medium-duty trucks (ZIL, MAZ).

- 9+ sheets: heavy tractor units (Volvo FH16).

4. Manufacturer

Reliable brands:

- Lesjöfors (Sweden) - for European trucks.

- Sachs (Germany) - universal springs for passenger cars and commercial vehicles.

- JSC "Spring Plant" (Russia) - a budget option for domestic equipment.

- DynaFlex (USA) - springs for tuning and SUVs.

Brand	Specialization	Average service life	Price range (per set)
Lesjöfors	Trucks Scania, Volvo	400–500 thousand km	50–120 thousand rubles.
Sachs	Passenger and commercial vehicles	200–300 thousand km	20–60 thousand rubles.
JSC "Spring Plant"	Domestic technology (KAMAZ, UAZ)	150–250 thousand km	10–30 thousand rubles.
DynaFlex	Tuning and SUVs	250–400 thousand km	70–150 thousand rubles.

⚠️ Attention: When purchasing springs for trucks with air suspension check if they come with emergency stops — without them, if the system depressurizes, the bridge may rest against the frame!

Replacing springs: step-by-step instructions and typical mistakes

Replacing springs is a labor-intensive operation that requires not only tools, but also knowledge. Let's look at the process using an example KAMAZ-5320 truck:

Required tool:

• 🔧 Jack with a lifting capacity of at least 10 tons.
• 🔧 Set of sockets and keys (including 27 mm and 32 mm).
• 🔧 Puller for tension clamps.
• 🔧 Torque wrench (tightening torque - 180–220 N m).
• 🔧 Crowbar and hammer (for dismantling soured fingers).

Step by step process:

1. Raise the axle with a jack, making sure that the car is standing on supports (not just on a jack!).
2. Disconnect the shock absorbers and anti-roll bars (if equipped).
3. Remove the tie clamps, starting with the outer sheets.
4. Knock out the pins securing the spring to the axle and frame (pre-treat WD-40).
5. Install a new spring, observing the order of the leaves (the main leaf should be on the bottom!).
6. Tighten the clamps and pins firmly 200 Nm (for KAMAZ).
7. Check the geometry of the bridge - adjust the wheel alignment if necessary.

Typical mistakes:

• ❌ Incorrect tightening torque - leads to weakening of clamps and squeaking.
• ❌ Placing sheets in the wrong order - the spring will work harder or softer than necessary.
• ❌ Ignoring bushing checks — worn bushings will lead to backlash in the bridge.
• ❌ Replacing only one spring - if you change on one axis, change on the second (otherwise there will be a skew).

FAQ: Frequently asked questions about springs

Is it possible to install springs from another car model?

Theoretically it is possible, but only if they match:

- Length and width of the spring.

- Number of sheets and their thickness.

- Type of fastening (pins, bushings).

- Load capacity (springs cannot be installed from cars on truck!).

It is better to use springs recommended by the manufacturer, or analogues with the same parameters. For example, springs from GAZ-66 suitable for UAZ-469, but not for KAMAZ.

How to check springs without removing them?

Visually inspect the springs:

- Cracks or tears in the sheets.

- Corrosion on more than 30% of the area.

- Play between sheets (if the clamps are loose).

- Deflection: if the distance between the bridge and the frame has decreased by 10% or more, the spring has “sat down.”

Also pay attention to the behavior of the car:

- Creak when driving over bumps.

- “Sagging” of the body on one side.

- Deterioration in handling (the car “scours” along the road).

What is the difference between springs for the front and rear axles?

Front axle springs are usually:

- Shorter and wider (for better handling).

- They have greater rigidity (since the front axle bears the load from the engine).

- More often completed anti-roll bars.

Rear axle springs:

- Longer and thinner (to soften the load).

- There may be multi-leaf (for example, in trucks).

- They often have additional buffers to limit travel.

Is it possible to repair a spring (for example, weld a crack)?

No, it is absolutely forbidden to repair springs by welding! Reasons:

- Welding disrupts the structure of the metal, making it brittle.

- The spring bends - the weld seam will not withstand the load.

- Risk of breaking while driving (especially dangerous for trucks!).

The only acceptable “repair” is the replacement of individual sheets (if the spring is collapsible). But even in this case, it is better to install a new spring.

How often should springs be checked?

Recommended frequency:

- For passenger cars: once every 50–60 thousand km.

- For trucks: once every 30–40 thousand km or before long flights.

- For SUVs: after every serious off-road.

Mandatory check:

- After an accident or a strong blow to the suspension.

- When replacing shock absorbers or silent blocks.

- If the car begins to “sag” or a creaking sound appears.